title: A class V chitinase from Arabidopsis thaliana: gene responses, enzymatic properties, and crystallographic analysis.
abstract: Expression of a class V chitinase gene (At4g19810, AtChiC) in Arabidopsis thaliana was examined by quantitative real-time PCR and by analyzing microarray data available at Genevestigator. The gene expression was induced by the plant stress-related hormones abscisic acid (ABA) and jasmonic acid (JA) and by the stress resulting from the elicitor flagellin, NaCl, and osmosis. The recombinant AtChiC protein was produced in E. coli, purified, and characterized with respect to the structure and function. The recombinant AtChiC hydrolyzed N-acetylglucosamine oligomers producing dimers from the non-reducing end of the substrates. The crystal structure of AtChiC was determined by the molecular replacement method at 2.0 Å resolution. AtChiC was found to adopt an (β/α)(8) fold with a small insertion domain composed of an α-helix and a five-stranded β-sheet. From docking simulation of AtChiC with pentameric substrate, the amino acid residues responsible for substrate binding were found to be well conserved when compared with those of the class V chitinase from Nicotiana tabacum (NtChiV). All of the structural and functional properties of AtChiC are quite similar to those obtained for NtChiV, and seem to be common to class V chitinases from higher plants.
authors.affiliation: Department of Advanced Bioscience, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohnuma
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Numata
authors.forename: Takuo
authors.initials: T
authors.lastname: Osawa
authors.forename: Mamiko
authors.initials: M
authors.lastname: Mizuhara
authors.forename: Outi
authors.initials: O
authors.lastname: Lampela
authors.forename: André H
authors.initials: AH
authors.lastname: Juffer
authors.forename: Karen
authors.initials: K
authors.lastname: Skriver
authors.forename: Tamo
authors.initials: T
authors.lastname: Fukamizo
mesh_terms: D000040:Abscisic Acid / Q000009:adverse effects; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002688:Chitinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000009:adverse effects; D005408:Flagellin / Q000009:adverse effects; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D009995:Osmosis / Q000502:physiology; D054883:Oxylipins / Q000009:adverse effects; D010937:Plant Growth Regulators / Q000378:metabolism; D012965:Sodium Chloride / Q000009:adverse effects
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D005408:Flagellin; D012965:Sodium Chloride; C011006:jasmonic acid; D000040:Abscisic Acid; D002688:Chitinases